LACK-LESTER: Red Sox ace Jon Lester allowed three home runs in in his first start of the season, a 9-5 loss to the Rangers in Arlington, Texas. Photo: EPA

MIAMI — Lucas Duda is no longer an unknown quantity in the Mets clubhouse.

The rookie outfielder arrived in awe as a September call-up last season, but after receiving regular playing time for a month then leading the Mets in at-bats during spring training, he will feel at home tonight when he starts in left field against the Marlins.

With Jason Bay (ribcage) on the disabled list for at least another week, Duda will be the starting left fielder. Willie Harris got the start last night because he had reached base 11 times in 22 career plate appearances against Florida ace Josh Johnson. He went 2 for 4 with a run scored in the Mets’ 6-2 loss.

Duda’s chance begins tonight.

“Obviously you want Jason Bay in left field, you don’t want me,” said Duda, who flew out to shallow left field in his only at-bat at a pinch hitter in the sixth inning. “But all the guys, it’s a great group of guys here, have come up to me and offered congratulations. It’s a little better than being called up in September, because I know the guys a little better. I know what to expect, in a sense.”

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Manager Terry Collins‘ pre-Opening Day meeting focused on reminding the Mets they have talent.

“This doesn’t have to be us against the world,” Collins said. “What we’ve got to let them know is if we get out there and we play the game the way our guys are capable of playing and we keep them out there, then we’re going to have success.

“The expectations in that room are the only expectations I give a [crud] about. I don’t care what the perception is on the outside.”

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Jon Niese, who will start tonight’s game for the Mets, pitched two stinkers at Sun Life Stadium last season. That included last Sept. 22, when he allowed six runs over 5 2/3 innings against the Marlins.

In his other career start here, last May 16, Niese was forced to leave the game with a hamstring injury he sustained while fielding a bunt. The Mets subsequently placed Niese on the disabled list and called up R.A. Dickey from Triple-A Buffalo.